So i am not completely new to fish keeping. My parents have had a tank since i was little and i have always understood and helped them to keep it up. That being said this may sound like a silly question. I have an established 15 gal tank. I had 2 balloon mollies which then had fry. Im down to 8 fry. I moved to 2 adult balloon mollys to my parents tank since mine i felt was starting to get crowded. Then someone gave me 3 red cherry shirmp. I put them in my tank to see how everything would go. I now only can find 2. Idk what happened to the male but i havent seen him in a few days. While reading up on these adorable guys i discovered that gravel is ok but i would like to change the tank to the fluval shimp substrate. Now for the (strange?) question. Can i take all the gravel out and put the new substrate in and then put the fish back in? Since it is an already established tank i dont see anything wrong with this BUT i dont want to do anything until i get an answer. Im not new to fish keeping but this is my first experiences with shrimp. Sorry if this sounds stupid but the only time i have ever changed substrate was to set up a brand new tank.